Coating thickness gauge



FIG. 1 is a front view of a coating thickness gauge showing my new design.

FIG. 2 is a left side view thereof.

FIG. 3 is a right side view thereof.

FIG. 4 is a rear view thereof.

FIG. 5 is a bottom view thereof; and,

FIG. 6 is a top view thereof. 

The ornamental design for a coating thickness gauge, as shown and described. 